package com.example.demo.mqserver;

/**
 * Created with IntelliJ IDEA.
 * Description
 * User: 杰
 * Date: 2023 -08 -02
 * Time: 12:48
 */

import com.example.demo.common.Consumer;
import com.example.demo.common.MqException;
import com.example.demo.mqserver.core.*;
import com.example.demo.mqserver.datacenter.DiskDataCenter;
import com.example.demo.mqserver.datacenter.MemoryDataCenter;

import java.io.IOException;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * 通过这个类, 来表示虚拟主机.
 * 每个虚拟主机下面都管理着自己的交换机, 队列, 绑定, 消息, 数据.
 * 同时提供 api 供上层调用.
 * 针对 VirtualHost 这个类, 作为业务逻辑的整合者, 就需要对于代码中抛出的异常进行处理了.
 */
public class VirtualHost {
    private String virtualHostName;
    private MemoryDataCenter memoryDataCenter = new MemoryDataCenter();
    private DiskDataCenter diskDataCenter = new DiskDataCenter();
    private Router router = new Router();
    private ConsumerManager consumerManager = new ConsumerManager(this);

    // 操作交换机的锁对象
    private final Object exchangeLocker = new Object();
    // 操作队列的锁对象
    private final Object queueLocker = new Object();

    public String getVirtualHostName() {
        return virtualHostName;
    }

    public MemoryDataCenter getMemoryDataCenter() {
        return memoryDataCenter;
    }

    public DiskDataCenter getDiskDataCenter() {
        return diskDataCenter;
    }

    public VirtualHost(String name) {
        this.virtualHostName = name;
        // 对于MemoryDataCenter 来说, 不需要额外的初始化操作, 只要对象 new 出来就行了.
        // 但是对于DiskDataCenter 来说, 需要进行初始化操作, 建库建表.
        diskDataCenter.init();
        // 另外需要针对硬盘的数据, 进行恢复到内存中.
        try {
            memoryDataCenter.recovery(diskDataCenter);
        } catch (IOException | ClassNotFoundException | MqException e) {
            e.printStackTrace();
            System.out.println("[VirtualHost] 恢复内存数据失败!");
        }
    }

    // 创建交换机
    // 如果交换机不存在, 则创建, 如果存在, 直接返回.
    // true 表示创建成功, false 为创建失败.
    public boolean exchangeDeclare(String exchangeName, ExchangeType exchangeType, boolean durable, boolean autoDelete,
                                   Map<String, Object> arguments) {
        // 把交换机的名字加上 虚拟主机作为前缀.
        exchangeName = virtualHostName + exchangeName;
        try {
            synchronized (exchangeLocker) {
                // 1. 判断该交换机是否已经存在, 通过内存查询.
                Exchange existsExchange = memoryDataCenter.getExchange(exchangeName);
                if (existsExchange != null) {
                    // 该交换价已经存在!
                    System.out.println("[VirtualHost] 交换机已经存在! exchangeName=" + exchangeName);
                    return true;
                }
                // 2. 创建交换机, 先构造 Exchange 对象.
                Exchange exchange = new Exchange();
                exchange.setName(exchangeName);
                exchange.setType(exchangeType);
                exchange.setDurable(durable);
                exchange.setAutoDelete(autoDelete);
                exchange.setArguments(arguments);
                // 3. 把交换机对象写入硬盘 (前提是如果需要持久化存储)
                if (durable) {
                    diskDataCenter.insertExchange(exchange);
                }
                // 4. 交换机对象写入内存
                memoryDataCenter.insertExchange(exchange);
                System.out.println("[VirtualHost] 交换机创建完成! exchangeName=" + exchangeName);
                // 上述逻辑, 先写硬盘, 后写内存, 目的是为了防止写硬盘失败, 内存也就不用写了.
                // 如果先写内存的话, 内存写成功了, 硬盘写失败了, 这时候还需要把内存中的数据给删除掉.
            }
        } catch (Exception e) {
            System.out.println("[VirtualHost] 交换机创建失败! exchangeName=" + exchangeName);
            e.printStackTrace();
            return false;
        }
        return true;
    }

    // 删除交换机
    public boolean exchangeDelete(String exchangeName) {
        exchangeName = virtualHostName + exchangeName;
        try {
            synchronized (exchangeLocker) {
                // 1. 先找到对应的交换机
                Exchange toDelete = memoryDataCenter.getExchange(exchangeName);
                if (toDelete == null) {
                    throw new MqException("[VirtualHost] 交换机不存在无法删除!");
                }
                // 2. 删除硬盘上的数据
                if (toDelete.isDurable()) {
                    diskDataCenter.deleteExchange(exchangeName);
                }
                // 3. 删除内存中的交换机数据
                memoryDataCenter.deleteExchange(exchangeName);
                System.out.println("[VirtualHost] 交换机删除成功! exchangeName=" + exchangeName);
            }
        } catch (Exception e) {
            System.out.println("[VirtualHost] 交换机删除失败! exchangeName=" + exchangeName);
            e.printStackTrace();
            return false;
        }
        return true;
    }

    // 创建队列
    public boolean queueDeclare(String queueName, boolean durable, boolean exclusive, boolean autoDelete,
                                Map<String,Object> arguments) {
        // 把队列的名字, 拼接上虚拟主机的名字.
        queueName = virtualHostName + queueName;
        try {
            synchronized (queueLocker) {
                // 1. 判定队列是否存在.
                MSGQueue existsQueue = memoryDataCenter.getQueue(queueName);
                if (existsQueue != null) {
                    System.out.println("[VirtualHost] 队列已经存在! queueName=" + queueName);
                    return true;
                }
                // 2. 创建队列对象.
                MSGQueue queue = new MSGQueue();
                queue.setName(queueName);
                queue.setDurable(durable);
                queue.setExclusive(exclusive);
                queue.setAutoDelete(autoDelete);
                queue.setArguments(arguments);
                // 3. 写硬盘
                if (durable) {
                    diskDataCenter.insertQueue(queue);
                }
                // 4. 写内存
                memoryDataCenter.insertQueue(queue);
                System.out.println("[VirtualHost] 创建队列成功! queueName=" + queueName);
            }
        } catch (Exception e) {
            System.out.println("[VirtualHost] 创建队列失败! queueName=" + queueName);
            e.printStackTrace();
            return false;
        }
        return true;
    }

    // 删除队列
    public boolean queueDelete(String queueName) {
        queueName = virtualHostName + queueName;
        try {
            synchronized (queueLocker) {
                // 1. 根据队列名字, 查询下当前队列对象
                MSGQueue queue = memoryDataCenter.getQueue(queueName);
                if (queue == null) {
                    throw new MqException("[VirtualHost] 队列不存在! 无法删除! queueName=" + queueName);
                }
                // 2. 删除硬盘数据
                if (queue.isDurable()) {
                    diskDataCenter.deleteQueue(queueName);
                }
                // 3. 删除内存数据
                memoryDataCenter.deleteQueue(queueName);
                System.out.println("[VirtualHost] 删除队列成功! queueName=" + queueName);
            }
        } catch (Exception e) {
            System.out.println("[VirtualHost] 删除队列失败! queueName=" + queueName);
            e.printStackTrace();
            return false;
        }
        return true;
    }

    // 创建绑定
    public boolean queueBind(String queueName, String exchangeName, String bindingKey) {
        queueName = virtualHostName + queueName;
        exchangeName = virtualHostName + exchangeName;
        try {
            synchronized (exchangeLocker) {
                synchronized (queueLocker) {
                    // 1. 判定当前的绑定是否已经存在了.
                    Binding existsBinding = memoryDataCenter.getBinding(exchangeName,queueName);
                    if (existsBinding != null) {
                        throw new MqException("[VirtualHost] binding 已经存在! queueName=" + queueName +
                                ", exchangeName=" + exchangeName);
                    }
                    // 2. 验证 bindingKey 是否合法.
                    if (!router.checkBindingKey(bindingKey)) {
                        throw new MqException("[VirtualHost] bindingKey 非法! bindingkey=" + bindingKey);
                    }
                    // 3. 创建 Binding 对象
                    Binding binding = new Binding();
                    binding.setExchangeName(exchangeName);
                    binding.setQueueName(queueName);
                    binding.setBindingKey(bindingKey);
                    // 4. 获取一下对应的交换机和队列, 如果交换机或者队列不存在, 这样的绑定也是无法创建的.
                    MSGQueue queue = memoryDataCenter.getQueue(queueName);
                    if (queue == null) {
                        throw new MqException("[VirtualHost] 队列不存在! queueName=" + queueName);
                    }
                    Exchange exchange = memoryDataCenter.getExchange(exchangeName);
                    if (exchange == null) {
                        throw new MqException("[VirtualHost] 交换机不存在! exchangeName=" + exchangeName);
                    }
                    // 5. 写硬盘 (前提是队列和交换机都是持久化,否则绑定持久化没有意义)
                    if (queue.isDurable() && exchange.isDurable()) {
                        diskDataCenter.insertBinding(binding);
                    }
                    // 6. 写入内存
                    memoryDataCenter.insertBinding(binding);
                    System.out.println("[VirtualHost] 绑定创建成功! exchangeName=" + exchangeName +
                            ", queueName=" + queueName);
                }
            }
        } catch (Exception e) {
            System.out.println("[VirtualHost] queueBind 绑定失败!");
            e.printStackTrace();
            return false;
        }
        return true;
    }

    // 解除绑定
    public boolean queueUnbind(String queueName, String exchangeName) {
        queueName = virtualHostName + queueName;
        exchangeName = virtualHostName + exchangeName;
        try {
            synchronized (exchangeLocker) {
                synchronized (queueLocker) {
                    // 1. 获取 binding 看是否已经存在
                    Binding binding = memoryDataCenter.getBinding(exchangeName,queueName);
                    if (binding == null) {
                        throw new MqException("[VirtualHost] 删除绑定失败! 绑定不存在! exchangeName=" + exchangeName +
                                ",queueName=" + queueName);
                    }
                    // 2. 删除硬盘上的数据.(无论绑定是否持久化了, 都尝试从硬盘上删一下, 就算不存在, 这个删除也没有任何副作用)
                    diskDataCenter.deleteBinding(binding);
                    // 3. 删除内存上的数据
                    memoryDataCenter.deleteBinding(binding);
                    System.out.println("[VirtualHost] 删除绑定成功!");
                    return true;
                }
            }
        } catch (Exception e) {
            System.out.println("[VirtualHost] 删除绑定失败!");
            e.printStackTrace();
            return false;
        }
    }

    // 发送消息到指定交换机 / 队列中
    public boolean basicPublish(String exchangeName, String routingkey, BasicProperties basicProperties, byte[] body) {
        try {
            // 1. 转换交换机的名字
            exchangeName = virtualHostName + exchangeName;
            // 2. 检查 routingkey 是否合法.
            if (!router.checkRoutingKey(routingkey)) {
                throw new MqException("[VirtualHost] routingKey 非法! routingKey=" + routingkey);
            }
            // 3. 查找交换机对象
            Exchange exchange = memoryDataCenter.getExchange(exchangeName);
            if (exchange == null) {
                throw new MqException("[VirtualHost] 交换机不存在! exchangeName=" + exchangeName);
            }
            // 4. 判定交换机的类型
            if (exchange.getType() == ExchangeType.DIRECT) {
                // 按照直接交换机的方式来转发消息
                // 以 routingKey 作为队列的名字, 直接把消息写入指定的队列中.
                // 此时, 就可以无视绑定关系.(直接将消息放到队列中)
                String queueName = virtualHostName + routingkey;
                // 5. 构造消息对象
                Message message = Message.createMessageWithId(routingkey,basicProperties,body);
                // 6. 查找该队列名对应的对象
                MSGQueue queue = memoryDataCenter.getQueue(queueName);
                if (queue == null) {
                    throw new MqException("[VirtualHost] 队列不存在! queueName=" + queueName);
                }
                // 7. 队列存在, 直接给队列中写入消息.
                sendMessage(queue,message);
            } else {
                // 按照 fanout 和 topic 的方式转发
                // 5. 找到该交换机关联的所有绑定, 并遍历这些绑定对象.
                ConcurrentHashMap<String, Binding> bindingsMap = memoryDataCenter.getBindings(exchangeName);
                for (Map.Entry<String, Binding> entry : bindingsMap.entrySet()) {
                    // 获取到绑定对象, 判定对应的队列是否存在.
                    Binding binding = entry.getValue();
                    MSGQueue queue = memoryDataCenter.getQueue(binding.getQueueName());
                    if (queue == null) {
                        // 此处不抛异常, 不能因为一个队列的失败, 影响到其他队列的消息的传输.
                        System.out.println("[VirtualHost] basicPublish 发送消息时, 发现队列不存在! queueName=" + binding.getQueueName());
                        continue;
                    }
                    // 构造消息对象
                    Message message = Message.createMessageWithId(routingkey, basicProperties, body);
                    // 判定这个消息是否能转发给队列
                    // 如果是 fanout, 所有绑定的队列都要转发
                    // 如果是 topic , 还要判定下, bindingkey 和 routingkey 是否匹配.
                    if (!router.route(exchange.getType(),binding,message)) {
                        continue;
                    }
                    // 转发消息给队列
                    sendMessage(queue,message);
                }
            }
        } catch (Exception e) {
            System.out.println("[VirtualHost] 消息发送失败!");
            e.printStackTrace();
            return false;
        }
        return true;
    }

    private void sendMessage(MSGQueue queue, Message message) throws IOException, MqException, InterruptedException {
        // 此处发送消息, 就是把消息写入到 硬盘和内存上.
        int deliverMode = message.getDeliverMode();
        // deliverMode 为 1, 不持久化, deliverMode 为 2 表示持久化.
        if (deliverMode == 2) {
            diskDataCenter.sendMessage(queue,message);
        }
        // 写入内存
        memoryDataCenter.sendMessage(queue,message);

        // 还需要补充一个逻辑 , 通知消费者可以进行消费消息了.
        consumerManager.notifyConsume(queue.getName());
    }

    // 订阅消息
    // 添加一个队列的订阅者, 当队列收到消息之后, 就要把消息推送给对应的订阅者.
    // consumerTag: 消费者的身份标识
    // autoAck: 消息被消费之后, 应答的方式 为 true 时是自动应答. 为 false 是手动应答
    // consumer: 是一个回调函数, 此处类型设定成函数式接口, 这样后续调用 basicConsume 并且传实参的时候, 就可以写作 lambda 的样子了.
    public boolean basicConsume(String consumerTag, String queueName, boolean autoAck, Consumer consumer) {
        // 构造一个 ConsumerEnv 对象, 把这个对应的队列找到, 再把这个 Consumer 对象添加到该队列中.
        queueName = virtualHostName + queueName;
        try {
            consumerManager.addConsumer(consumerTag, queueName, autoAck, consumer);
            System.out.println("[VirtualHost] basicConsume 成功! queueName=" + queueName);
            return true;
        } catch (Exception e) {
            System.out.println("[VirtualHost] basicConsume 失败! queueName=" + queueName);
            e.printStackTrace();
            return false;
        }
    }

    public boolean basicAck(String queueName, String messageId) {
        queueName = virtualHostName + queueName;
        try {
            // 1. 获取到消息和队列
            Message message = memoryDataCenter.getMessage(messageId);
            if (message == null) {
                throw new MqException("[VirtualHost] 要确认的消息不存在! messageId=" + messageId);
            }
            MSGQueue queue = memoryDataCenter.getQueue(queueName);
            if (queue == null) {
                throw new MqException("[VirtualHost] 要确认的队列不存在! queueName=" + queue.getName());
            }
            // 2. 删除他硬盘上的数据
            if (message.getDeliverMode() == 2) {
                diskDataCenter.deleteMessage(queue,message);
            }
            // 3. 删除消息中心的数据
            memoryDataCenter.removeMessage(messageId);
            // 4. 删除待确认的集合中的数据
            memoryDataCenter.removeMessageWaitAck(queueName,messageId);
            System.out.println("[VirtualHost] basicAck成功! 消息被成功确认! queueName=" + queueName + ", messageId=" + messageId);
            return true;
        } catch (Exception e) {
            System.out.println("[VirtualHost] basicAck失败! 消息确认失败! queueName=" + queueName + ", messageId=" + messageId);
            e.printStackTrace();
            return false;
        }
    }
}






















